These [are] the generations of the heavens and the earth,
when they were created
That is, the above account, delivered in the preceding chapter, is a history of the production of the heavens and earth, and of all things in them; the creation of them being a kind of generation, and the day of their creation a sort of birthday; see ( Genesis 5:1 ) ( Matthew 1:1 )
in the day that the Lord God made the earth, and the heavens;
meaning not any particular day, not the first day, in which the heavens and the earth were created; but referring to the whole time of the six days, in which everything in them, and relating to them, were made. Here another name is added to God, his name "Jehovah", expressive of his being and perfections, particularly his eternity and immutability, being the everlasting and unchangeable "I am", which is, and was, and is to come: this name, according to the Jews, is not to be pronounced, and therefore they put the points of "Adonai", directing it so to be read; and these two names, "Jehovah Elohim", or "Adonai" and "Elohim", with them make the full and perfect name of God, and which they observe is here very pertinently given him, upon the perfection and completion of his works.